Problem
The inspector backend (backend/app.py) uses v0.3 SDK types (FilePart, TextPart,
ClientEvent) that no longer exist in a2a-sdk v1.0+, which switched to protobuf types.
When the inspector's pyproject.toml requires >=1.0.0, the backend crashes on import.
When pinned to 0.3.x, the SDK's transport layer (a2a/client/transports/jsonrpc.py:181)
validates SSE events against v0.3 SendStreamingMessageResponse Pydantic models,
which reject v1.0 format responses ({"task": {...}} wrapper, no final field).
Impact
Agents implementing A2A spec v1.0 cannot be tested with the inspector.
Evidence
- TCK at 72.4% confirms the agent is v1.0 compliant
- Inspector fails with 14 Pydantic validation errors on every streaming call
Suggested fix
Update backend/app.py to use v1.0 SDK APIs and update the transport
validation to use v1.0 StreamResponse protobuf types.
Problem
The inspector backend (
backend/app.py) uses v0.3 SDK types (FilePart,TextPart,ClientEvent) that no longer exist in a2a-sdk v1.0+, which switched to protobuf types.When the inspector's
pyproject.tomlrequires>=1.0.0, the backend crashes on import.When pinned to
0.3.x, the SDK's transport layer (a2a/client/transports/jsonrpc.py:181)validates SSE events against v0.3
SendStreamingMessageResponsePydantic models,which reject v1.0 format responses (
{"task": {...}}wrapper, nofinalfield).Impact
Agents implementing A2A spec v1.0 cannot be tested with the inspector.
Evidence
Suggested fix
Update
backend/app.pyto use v1.0 SDK APIs and update the transportvalidation to use v1.0
StreamResponseprotobuf types.